Does chronic oral contraceptive use detrimentally affect C‐reactive protein or iron status for endurance‐trained women?

This secondary analysis compared basal CRP and iron parameters between 8 OCP-using and 8 eumenorrheic endurance-trained female athletes. Sample collection followed standardized exercise and nutritional control for 24 hours. Eumenorrheic females were tested in early-follicular and mid-luteal phases, and OCP users in quasi-follicular and quasi-luteal active pill phases. A main effect for group (p < 0.01) indicated higher average CRP in OCP users compared with eumenorrheic females regardless of cycle day, with median CRP approximately 2 mg/L in OCP users versus approximately 0.4 mg/L in eumenorrheic participants. Five OCP users were classified at intermediate cardiovascular risk and two at high risk, while seven of eight eumenorrheic females presented with CRP below 1 mg/L. Iron parameters showed some moderation across cycle phases influenced by basal CRP levels, but no linear relationship with CRP, serum iron, and ferritin was observed.